As of November, 4.1 million Americans have bought Halo 3 -- more than half of the current 7.9 million Xbox 360 owners in the United States.

"The power of Halo 3 is quite evident," said NPD analyst Anita Frazier in speaking with GameDaily. "When it released it drove hardware sales substantially... That is why content is so important - a killer game drives hardware adoption more than any other factor (including price cuts)."

By comparison (noting that Halo 3 has been out two months longer), Super Mario Galaxy has been purchased by 19 percent of all U.S. Wii owners so far (6 million). Nintendo says it's pleased with the service so far rendered by the Italian plumber.

"Galaxy will have extremely long life and will have extremely large numbers throughout that entire life," said Reggie Fils-Aime, president of NOA. "Mark my words, look in six months and no one will have any remembrance that [Galaxy] 'only' did 1.1 million copies in its first month."